Petroleum-refining process and reagent for the removal of sulphur



Patented Oct. 18, 1927.

UNITED STATES PATENT OFFICE.

FRANK C. AXTELL, OF SOUTH PASADENA, CALIFORNIA, ASSIGNOR TO AXTELL BE- SEARCH LABORATORIES,

CALIFORNIA.

1170., 015 LOS ANGELES, CALIFORNIA, A CORPORATION OF .PETBOLEUM-RE FINING PROCESS AND REAGENT FOR THE REMOVAL OF SULPH'OR.

11o Drawing.

tent; and that such sulphur has been re-' moved only at considerable expense, to comply with commercial requirementsj. 1 It is also well known that sulp uric acid has a separating action upon the ulphur compounds in these distillates,-ten ingto combine therewith and/or to separate them from the oils; but, as is also well knowm the I action of the sulphuric acid may alsd be exerted upon various desired hydrocarbon constituents of the distillates (such as the unsaturated and aromatic hydrocarbons that may be present)causing polymerization, oxidation and/or sulphonation of these or other valuable constituents of the oil, which have thus been incidentally deposited and .d rawn off, with the sludge, in such percentages as to involve a loss that is extremely serious both to the refiner and to the public and to the best of my knowledge, there is at the present timeno method whereby the action of the sulphuric acid may be controlled to the point of removing undesirable constituents and leavin the desirable constituents, the exercise 0 the control varying with the quality of the oil.

Most petroleum distillates' obtained from western oils contain considerable quantities of unsaturated and/or aromatic hydrocar- 40 bons,-this being particularly true of distillates and residuals from asphaltic base oils, from shale oils and/or from cracked oils. Such distillates may contain from 20% to 50% of unsaturated hydrocarbons,--

which possess great energy value but which tend to go into any ordinary sulphuricacid sludge, as heretofore produced. v

Sulphuric acid, as'used in quantities and strength required to reduce the amount of sulphur in hydrocarbons to a permissible uantity, has carried with it, into the acid udge, from 5% to 25% of the original Application filed December 27, 1926. Serial No. 157,427.

volume of the oil subjected to treatment. For example, in the treating of cracked distillates (in which the sulphur compounds are.

generally very resistantto acid treatment) lt'has been common to use a relatively large amount of highly concentrated sulphuric acid, in order to secure a fuel with a relatively low percentage of sulphur and to conform with commercial specifications; the refining loss, due to the mentioned polymerization, sulphonation and oxidation effects of sulphuric acid upon unsaturated hydrocarbons and/0r aromatic hydrocarbons, has accordmgly been very great; and its serious-' ness' can be. appreciated only when it is realized that the action referred to tends to eliminate from the distillates some of those constituents which are of greatest value and which tend to an anti-knocking effect,-comparable with that-obtained (at considerable expense and not without hazard) by the use of tetra-ethyl lead.

Now, I have discovered that the'polymerizing, oxidizing and sulphonating powers or actions of sulphuric acid can be very favorably modified by the addition thereto'of a substance .or substances capable of reacting therewith and/or overcoming (by nonaqueous dilution, or by consuming or reducing or inhibiting the same) its capacity for polymerization; I find that these desired etfliectsv can be obtained without adversely afl'ectin its ailinity for sulphur compounds; and also find that, when mypreferred satisfied acid reagent is mixed with hydrocarbons to be refined, it appears content to combine with the sulphur-containing and nitrogenous compounds therein,forming a sludge, of low hydrocarbon content, which is capable of being quickly separated asa mixture of socalled sulphur oils containing acid.

More specifically, I have discovered that if fuming sulphuric acid (preferably containing a considerable percentage of 80,) be

admixed and/or agitated (as may be done at an ordinary temperature) with an excess quantity of an aromatic hydrocarbon such as commercial benzene, toluene or xylene, or a mixtureof these (the mentioned excess being such that, after agitation of the mixture, a layer of the aromatic hydrocarbon or hydrocarbon mixture separates ancl rises, to constithose tically no power of oxidation and/or sulpho- I anhydride.

nation of unsaturated or other desired hydrocarbons.

I have also discovered that, upon treating hydrocarbon distillates with an acid reagent derived substantially as above indicated, and thereby apparently satisfied as to its polymerizing, oxidizing and sulphonating qualities, the sulphur compounds in any such hydrocarbon distillate (or in any other sulphur-containing material treated in the manner referred to) are so combined either with the sulphuric acid or With the sulphuric anhydride, or with aromatic derivatives produced thereby, as to form a fluent acid slud e, having comparatively small volume, w ich is readily separable from the hydrocarbons; and I have discovered also that such ortion of the sulphur content of the treated distillate or other material as remains in the oil is likely to have undergone transformation into comparatively complex sulphur compounds,these being ordinarily of such high boiling points that, upon a subsequent distillation, they tend to remain very largely in the still bottoms, after commercial gasoline and/or any other desired products are driven off by the distillation, economically producing a substantially white and sweet gasoline of very low sulphur content, or other products of corresponding purit p As is known, various aromatic hydrocarbons such as benzene, toluene and xylene dissolve in highly concentrated or fuming sulphuric acid without undergoing appreciable polymerization or oxidation. The products thus obtained, including those which result from so-called'side-reactions, are not single definite chemical compounds, being 'mixtures of certain aromatic sulpho acid compounds, and other products of reaction, M

with free sulphuric acid and/or sulphuric Accordingly, While the acid mixtures referred to must contain certain known or unknown sulpho acids, it is not my purpose separately to use any single definite compound, as the use thereof would be unduly expensive and also apparently less effective, for my indicated purpose, than the use of the reagent mixtures herein described. y r

' The exact proportions of theiingredients of my reagent mixtures may vary. I find, for instance, that if fuming sulphuric acid be treated at ordinary temperatures with an excess of commercial benzene, toluene or emon xylene, or with mixtures of the above (preferably in such proportions that, after agitation, an excess of the hydrocarbon or hydrocarbons separates,--rising to the surface of the mixture and so leaving the combined acid mixtures) the resultant mixture or reagent may be used either by itself or blended with a further quantity of sulphuric acid; and that it, in either case, forms an excellent reagent forv use upon petroleum oils and distillates for the removal of sulphur and-objectionable compounds; and I emphasize that by the use of various blends of my reagent with further quantities of sulphuric acid (depending upon the quality of the treated oil), the polymerizing, oxidizing and sulphonating properties of sulphuric acid on the unsaturated and other hydrocarbonsin the treated oil can be either entirely obviated or satisfactorily controlled,-so that, when such petroleum or other distillates are treated as hereinafter described, the refining losses may be reduced to a minimum. By proceduresof the general character referred to, the operator is enabled to use even a relatively large proportion of .the mentioned reagent mixture to the oil treated,

without suffering those heavy refining losses which have been referred to as incidental to the separate use of sulphuric acid. The foregolng constitutes a peculiarly valuable treatment in the case of cracked distillates,

in that the proportion of sulphur compounds therein is high and in that the, sul- V phur compounds in such distillates are comwith my new reagent, a large proportion of such sulphur compounds combines directly With the aromatic acid reagent, remaining dissolved therein or combined therewith.

Upon separation of the acid sludge from the oil, a part of the sulphur content ,of the sludge may be separated directly by diluting the latter with Water; but another portion of the sulphur content of the original distillate is evidently acted upon chemically by the reagent, with production of-complex sulphur compounds of very high boilingpoint. Although a portion of the latter may remain dissolved in the ,oil, most of this portion may be economically separated by mere retention in the still, upon a subsequent distillation as hereinafter described.

In view of the foregoing, it will be understood to be a general object of my vention'to provide a' rocess for the treatment of hydrocarbon 'stillates, or the like,

anhydride thereon.

whereby deleterious compounds may be cheaply and expeditiously removed. without 'by refined distillates may be produced without undue collateral loss in volume, in fuel value or in other desired properties, during or'subsequent to such treatment.

It is a specificobject ,of this invention to provide, for use in the separation of sulphur compounds from desired hydrocarbons, a reagent which includes sulphuric acid and/or sulphuric anhydride in admixture with a nonaqueous diluent,-such as an aromatic body or bodies, or derivatives produced by the action of sulphuric acid or sulphuric A further, object of my invention is to provide a rea ent of the class described which is suscepti le to the mixture therewith, of sulphuric acid in the treatment of oils, whereby a definite control may be had in the desulphurizing and refining of the oils treated.

It is a further object of my invention to provide, for the use mentioned, a reagent containing one or more aromatic sulphonic acids and/or derivatives thereof, these bein preferably employed in the presence of su huric acid and/or sulphuric anhydride and in the substantial absence of water; and itis a specific object of this invention to utilize what I hereinafter refer to as a sulphonicsulphuric reagent mixture, of the general character indicated, in the commercial production of colorless and sweet gasollnes, having high calorific value and unusual anti-knocking properties, or in the production of other hydrocarbon mixtures of corresponding merit,according to the fraction or material treated and/or the products desired.

In applying my invention to the treatment of cracked petroleum distillates, for instance, I may proceed according to the following outline: (1) preparing the reagent by combining a nonaqueous sulphuric acid (preferably fuming) with commercial or other benzene, toluene and/0r xylene; I may (2) treatthe distillate by agitation or contact with a suitable quantity of this reagent, 3*) allow the acid sludge to. settle, and then (4) separate thetreated distillate from the.

acid sludge. I may then (5) treat the distillate with a small quantity of a good basic clay, (6) separate the clay from the distillate by sedimentation or filtration, (7) agi tion.

tate the treated distillate with a. small quantity of a strong solution of an alkali such as caustic soda, caustic potash, or a carbonate of sodium or potassium, (8) separate the distillate from the aqueous alkaline solution and (9) finally subject the oil so obtainedto another distillation,-any sulphur which failed to enter the sludge then remaining mostly in the still bottoms.

As a specific illustration of the method employed and the results obtained, I may give the following: A given quantity of an end-point gasoline distillate produced by previous cracking, said distillate having an end boiling-point of 437 F. and containing about 0.68 percent of sulphur, was treated with twenty-five pounds per barrel of m reagent, as made by chemically and physically saturating a fuming sulphuric acid.

with benzene at an ordinary temperature. Upon beginning the agitation ofthe treated oil-plus-reagent mixture, it assumed a milky appearance; and upon continued agitation it gradually cleared up, finally becoming perfectly transparent and of a ver light yellow c0lor,an acid sludge settling, in small volume, tothe bottom of the container. The oil was then separated from the acid sludge '(the refining loss being about 2.56 percent by volume) and it was next treated with about four pounds per barrel of socalled Death Valley clay, being agitated for five minutes therewith. and then filtered,- the' filtrate being practically colorless.

The filtered oil -was then agitated with about three pounds per barrel of a 33 percent aqueous solution of sodium hydroxide, and, was separated from the aqueoussolu- At this point the oil was found to have a sulphur content of 0.30 percent.

The treated oil, hereinafter referred to as refined gasolinefwas then blended with a The blended distillate was then distilled with a small quantity of caustic potash solution, until the temperature at the dephlegmator head reached about 225 F. At this point steam was introduced into the still and the distillation continued until the original volume of the refined gasoline had passed over,-leaving the kerosene still-base in the still. The gasoline thus obtained, when separated from the condensed water and dried, showed a sulphur content of 0.11 per cent; whereas the kerosene still-base had a sulphur content of 1.0 per cent.

The acid sludge, which was so fluent as to necessitate no use of water in removing the same, when separated as above was diluted with water,--upon which the so-called sulphur oil separated and rose to the surface.

This oil was removed and washed and, upon analysis, was found contain 6.44: per cent of sulphur and to have a specific avity of 0.90. This is an unusually high sufidhur content for such oils,its character being apparently due to the fact that there occurred little or no polymerization of unsaturated hydrocarbons by, the described acid treatnaent.

Agasoline distillate produced as described has a pure hydrocarbon odor, is practically colorless and itysatisfies all the tests laid down the various standard specifications,in addition to which it contains practically the entire quantity of unsaturated hydrocarbons contained in the original distillate, and contributing to both thequality and quantity of the product. Further to iiiustrate the .value of my reagent mixture in the treatment of a cracked gasoline, and the fact that the proportions of the ingredients of this mixture may vary, I next mention a case-"in which a portion of the sulphur compounds contained in a cracked distillate were extremely resistant to ordinary treatment with plain sulphuric acid) A uantity, of a cracked -end point gasoline distillate containing 0.79 per cent of sulphur and 22 per cent'of unsaturates was agitated with twenty-five pounds per barrel of a reagent made by saturating a fuming sulphuric-acid (containing about per cent 80,) with a commercial benzene. To this acid mixture there was then added fuming sulphuric acid in such amount that the actual rea ent employed for treating the distillate consisted of 12% pounds per barrel of the hydrocarbon-saturated acid reagent and 12 pounds of fuming sulphuric acid containing- 20 per cent S0,. The distillate was then agitated with this latter acid and reagent mixture and treated exactly as has been described in the previous illustration. After this treatment, and before a final distillation, the sulphur content was found to have been reduced to 0.26 percent; and after distillation the unsaturates in the final distillate was 21.2 and the sulphur con tent 0.09 per cent. The refining loss in this case was 2.9 per cent after treatment with the aryl-acid reagent described.

In the foregoing, the inhibiting action ofv the aromatic hydrocarbons as regards the sulvfonating, polymerizing and oxidizing action of sulphuric acid on cracked petroleum distillates is strongly exhibited; and it is shown to be unnecessary. that the fuming sulphuric acid employed be entirely saturated with the aromatic hydrocarbons. However, I find that it is quite essential in the attainment of best results, to first prepare the reagent by completely saturating the acid with an aromatic hydrocarbon and then diluting this reagent with the further'addition of acid to the desired concentration, dependvaluable in the refining of so-called straightrun distillates-that is, distillates derived from crude petroleum by ordinary fractional distillation of the latter in a manner which i is well understood. The process employed in the treatment of such distillates may be exactlythe same in principle asthat employed in the illustrations hereinbefore given; except as the quantity and composition of the reagent employed may be varied to suit the character of the distillate or other oil treated. For instance, for refining an ordinary straight-run kerosene distillate, for the production of illuminating oil, such distillate may be treated with anywhere from five to fifteen pounds or more per barrel of either a saturated reagent mixture, or with a mixture having the indicated character but diluted to a diflerent ratio of free sul huric acid,=the other steps being presuma ly hereinbefore described; or the distillate, after treatment with a reagent mixture, may be washed withwater,-as ma also be done after treatment with alkali. be same general course may be followed in the treatment of other straight-run distillates.

My described reagent mixtures are of s cial value in the treatment of lubricating stocks, because, as well known, in the present method of treating these stocks, using large quantities of sulphuric acid, the polymerizing losses are extremely high; whereas, by treatment with this new aromatic hydrocarbon-sulphuric acid reagent, such polymerization and sulphonation losses are entirely or largely avoided.

From a consideration of the feregoing statements itwill be seen that the great advantages accruing from the use of my described reagents, in place of sulphuric acid,

' for the treatment of petroleum and its distillates, may be summed up as follows: Up to the present time it has been found impossible satisfactorily to remove the sul hur compounds from these cracked distil ates by means of sulphuric acid,-so that the refined cracked distillate would conform to standard specifications, without incurrin losses which were so high as to render suc treatment, commercially impracticable. On the other hand,by the use of my described reagents in which the polymerizing, oxidizin and sulphonating action of the sulphuric acidon the petroleum hydrocarbons 'is neutralized, modified or controlled by the admixture with such acid of an aryl body or benzol homologue such as benzene, toluene and/or xylene, as-herein described I am enabled to use, without incurrin the mentioned losses, as much of such m ified acid as may be required for the roper re moval of the sulphur compc-un s in such distillate.

' Referring again to the action of my reagent mixtures upon the sulphur compounds contained in petroleum distillates or analogous oils, it would appear that during the treatment of such distillates with the reagent mixtures, as hereinbefore described, a reaction occurs between the aromatic radicle or radicles contained in the acid and such sulphur compounds,-through which either a substitution or rearrangement occurs which is of such nature as to greatly modify the character of the ultimate reaction prod not, with apparent production of sulphur compounds having much higher boilingpoints than those contained in the untreated distillates; and it may be upon the mentioned facts and relationships, and upon the properties of the resultant bodies, that the value of my described reagents, or equivalent reagents for the purpose described, will be found, in final analysis, to depend. Except for such reactions and relations, it would appear impossible to obtain the results stated above, because upon distilling the untreated distillate exactly as has been described for the treated distillate, the sulphur compounds are carried over practically in their original quantity and concentration; but it should be understood that, although I now regard the mentioned aryl-bodies, or other bodies capable of undergoing various sulphonations, not only as diluents of the nevertheless contain acid sulphuric acid and/or anhydride, but also as solvents, catalysts and/or reacting bodies, I herein commit myself to no specific theory,--preferring to base my demands for protection merely. upon an adequate exposition of the materials and methods employed.

In one of the above specific illustrations of the use of my method of refining, I have stated that, in making the final distillation of the refined product, the addition of a small quantity of caustic potash solution to the contents of the still was made. The chief reason for this is the fact that among the sulphur compounds remaining in the oil (and some of which are formed by reactions already referred to) there are some that, although they are apparently or a neutral character under ordinary conditions, radicles; and,

' when these compounds are heated to a modfurther sta'bi erate or sufiiciently high temperature, in the absence of any alka i, the decomposition thereof yields free acids-which may react' unfavorably with desired hydrocarbons. However, if this heating takes place in the presence of a basicsubstance, such as potassium hydrate or sodium hydrate, the mentioned deleterious action is avoided. In

other words, the presence of the basic substances during heating has the eflects of still izing the sulphur com ounds and insuring their retention in or y the still-bottom; but the necessity for and the some cracking methods being more favorable than others to the retension of sulphur in still bottoms after use of my described reagents.

By way of a final emphasis upon the economic importance of my invention, I may comment that, at the of oils is being practiced to such an extent that approximately one hundred thousand barrels of cracked gasoline is being pro duced per day within the United States. This oil sustains a loss of at least ten per cent in refining, amounting to at least ten thousand barrels lost per day.

At an estimated value of ten cents per gallon of such lost fuel, or four dollars and twenty cents per barrel, this aggregates a daily loss of forty-two thousand dollars per day,aside from avoidable refining costs and the avoidable depletion of natural resources. The present practice throws away the most valuable power-producing elements -(high in energy and in anti-knocking qualities) that are present in the distillates derived by the cracking of oil.

Engineers skilled in explosive engine design and in the use of fuels in internal combustion engines are known to be seeking,

my process, a saving of some ten per cent in volume (unsaturates heretofore lost in refining) can be made, this saving may in view of the above considerations, actually be of less importance than the increase in power given by mynew fuel. v

Thus, for example, the travel radius of not only self propelled land and water devices but also that of air vehicles may be a proximately doubled, or a corresponding ecrease may be effected in the weight of fuel canried,this being a most important factor in air transportation, whether in peace or war.

Although I have herein described complete embodiments of my invention (in the resent time, cracking practice of which any water produced by drocarbons for the indicated uses may depend not only upon reactive relationships- .sulphonic-sulphuric stabilizing agent, or its equivalent, may be controlled, according as either benzene, toluene or xylene is-used in the making thereof. The boiling-points of the sulphur compounds, as produced by the indicated reactions, will increase in the order named,from benzene to xylene; and it will be seen that from this point of view (and depending upon the nature of the sulphur bodies to be removed) a comparatively impure benzene (containing considerable toluene and/or xylene) may actually be superior, for the purposes herein considered, to a more highly refined and expensive material. As a matter of theoretical interest, I may also mention that other stabilizing agents (containing, e. g., selenic acid or.

other non-volatile mineral acid) might be employed in place of ,those described, but are not now obtainable at satisfactory prices.

Concentrated selenic acid exerts very much the same action upon cracked distil- 'lates as does sulphuric acid; and while it has not exactly the same affinity for aromatic hydrocarbons as has sulphuric acid, I had that when selenic acid is treated with benzene, toluene or xylene, as described above in the case of sulphuric acid, its polymeriz ing action on the unsaturated hydrocarbons contained in cracket distillates 1s modified in the same way as in the case of sulphuric acid, and that a similar reaction between the sulphur compounds contained in the distillate and the aromatic hydrocarbon-selenio acid mixture occurs, with formation of sulphur and selenium compounds of high boilin'gipoints. 1 things considered, my experience points toward a ver extensive use of a rea ent such as may e formed by admixing a out three parts of a fuming sulphuric acid (such as may contain about twenty percent or slightly more of free S0,) with about one art of a commercial or below-standai'd benzenethe various reactions which prompltly .follow being effective to liberate enou water approximately to combine with the ee S0 producing additional H 804; but, althou hI have indicated that, depending upon ti may add more fuming sulphuric acid to a benzol-saturated mixture so rodueed (in order to preserve a substantially anhydrous condition, during treatment of said oil) I 'may also mention that I have, in other cases (as,in the treatment of a cracked distillate e character of the oil treated, I

having an endpoint at 437 F. and containing 0.68% of sulphur) obtained entirely satisfactory results by the use of a reagent prepared by adding to two parts of a benzolsaturated mixture (obtained in the general manner just described) one part of ordinary commercial sulphuric acid, containing about 95% of H 30, and about 5% of water. It is to be understood that, in the treatment of any oil of the character referred to, I employ my reagent as formed by the saturation 'of anhydrous sulphuric acid with an aromatic hydrocarbon, but in some instances where the oil to be treated contains certain unsaturates or refractory sulphur compounds which resist chemical treatment, I find that by adding to my reagent an additional quan tity of sulphuric acid, as hereinabove indicated, that a more intense action is obtained, resulting in the desired action on such resistant compounds. B using this added-sulphurc acid, I am ena led to perfectly .control the acid treatment of the oil which is a feature of major importance in the refining industry.

In the above illustrations of the use of my reagent and process, nothing has been said as to the preliminary treatment of the crude distillates, as received from the cracking- .units, for the removal of HS sulphur compounds contained in such crude distillates,

in practically all chemical reactions of this description, anincreas'e infthe temperature increases the intensity of the reaction or reactions; but it is common knowledge that the refiner must be governed by the character of the oil under treatment andby his experiences therewith.

Finally it should be understood that varlous features of this invention may be inde pendently employed; and also that numerous modifications of my invention might easily be devised, by those workers skilled in the arts to which this case relates, without involving the slightest departure from the spirit and scope of this invention, as the same is indicated above and in the following claims.

I claim as my invention 1. The method of preparing a reagent for treating mineral oils to reduce the sulphur content thereof, which comprises saturating loo ing the same with reagent mixture which results from saturating fuming sulphuric .acid with an aromatic hydrocarbon.

4. A method of reducing the sulphur content of mineral oils which comprises: treating the same with reagent mixture which results from saturating fuming sulphuric acid with an aromatic hydrocarbon, while maintaining the mixture within atmospheric temperatures.

5. A method of reducing the sulphur content of mineral oils which com rises: treating the same with a reagent mixture which results from saturating fuming sulphuric acid with a hydrocarbon of the benzol series.

6. A method of reducing the sulphur content of mineral oils which comprises: treatin the same with reagent mixture which resu ts from saturating fuming sulphuric acid with an aromatic hydrocarbon, said sulphuric acid containin SO in quantity sufficient to combine wit water formed by reactions between said acid and said hydrocarbon.

7. A method of reducing the sulphur content of mineral oils which comprises: treating the same witha reagent mixture comprising fuming sulphuric acid saturated with an aromatic hydrocarbon andthereafter separating a sulphur-containing sludge from the oil.

8. A method of reducing the sulphur content of mineral oils which comprises: treat-1 ing the same with a reagent comprising fuming sulphuric acid saturated with an aromatic hydrocarbon, thereafter separating a sulphur-containing sludge from theoil and redistilling the oil.

9. A method of reducing the sulphur content of mineral oils which comprises: treating the same with a reagent comprising fuming sulphuric acid saturated with an arO- matic hydrocarbon, thereafter separating a sulphur-containing sludge from the oil and redistilling the oil up to any certain end point.

10. A method of reducing the sulphur content of mineral oils without avoidable polymerizingand oxidizing effects-which comprises: treating the oil with a reagent comwith an aromatic hydrocarbon while maintaming the mixture within atmospheric temperatures; treating the oil with this reagent to form a sludge; separating the sludge from the oil and subjecting the resultant oil to distillation. v

11. A method of reducing the sulphur content of mineral oils without avoidable polymerizing and oxidizing etfects which comprises: treating the oil with a reagent comprising fuming sulphuric acid, saturated with an aromatic hydrocarbon while maintaining the mixture within atmospheric temperatures; treating the oil with this reagent to form a sludge; separating the sludge from the oil and subjecting the resultant oil to distillation.

12. A method of treating mineral oils containing sulphur bodies and unsaturates,

without avoidable polymerizing and oxidizing eifects, which comprises: subjecting fuming sulphuric acid to a preliminary treatment with an aromatic hydrocarbon which reduces its tendency toward pol merizing and oxidizing efiect on the oil wit out destroying its action upon sulphur bodies, and'then admixing the so-treated sulphuric acid with said oil. a

13. A method of treating mineral oils con taining sulphur bodies and unsaturates, without avoidable polymerizing and oxidizing effects, which comprises subjecting fuming sulphuric acid to a preliminary treatment with an aromatic hydrocarbon which increases its tendency to elevate the boilingpoint of said sulphur bodies; then reacting upon the oil with the so-treated acid; separating a resultant sludge from the oil, conta ning some sulphur bodies, neutralizing residual acid in the oil; separating .the productsof neutralization from the oil; and subnot.

15. A non-sulphonating, non-polymerizing, non-oxidizing reagent for treating petroleum oils comprising a solution consist.- ing of fuming sulphuric acid saturated with an aromatic hydrocarbon.

. adding sulphuric acid to the resultant prod- 16. A non-sulphonating, non-polymeriz-v I ing, non-oxidizing reagent for treating petroleum oils consisting of a solution composed of fuming sulphuric acid saturated with an'aromatic hydrocarbon to which solution a further addition of sulphuric acid has pris ng fuming sulphuric acid, saturated ing efiects, which comprises su jecting said oils to a treatment with a reagent comprising a solution composed of fiiining sulphuric acid, saturated With'an aromatic hydrocar bon, separating the sludge, resulting from said treated oil, from the oil, neutralizing the separated oil with an alkali, separating the products of neutralization fromf the oil, adding: a still base and an alkali to the so treated neutralized oil and subjecting the mixture of still base, alkali and treated oil to a distillation. I i

18. The method of treating mineral oils containing sulphur bodies and unsaturates Without avoidable polymerizing and oxidizing efi'ects, which comprises subjecting said oils to a treatnf ent with a reagent-consisting of a solution'compased of fuming sulphuric acid, saturated with an aromatic hydrocan bon, to which addition of sulphuric acid has been made, separating the; sludge, resulting from said treated oil, fronflhe oil,,-neutralizing residual acid in the separated oil with an alkali, separating the products of neutralization from the oil, adding a Stili base and an alkalito the so treated neutralized oil and subjecting the mixture of still base, alkali and treated oil to a distillation.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 20th nlay of December, 1926;

FRANK o. AXTELLZ 

